The present invention relates to methods for decomposing organic materials into hydrogen gas and elemental carbon in the form of carbon black, and to a smaller extent carbon monoxide. More particularly, the present invention is directed to an improved method of processing and converting organic materials, including organic waste materials such as non-pretreated infectious hospital wastes, refinery wastes, paper wastes, food processing wastes, and other similar solid and liquid organic wastes, into carbon, preferably in the form of carbon black, by exposing the organic material to a sufficiently intense field of radiant energy that primarily promotes the chemical reactions resulting in the decomposition of the organic materials into hydrogen and carbon and small amounts of carbon monoxide.
Carbon black is a low density, porous form of carbon. It is used in the fabrication and manufacture of many items including automobile tires and audio and video tapes. Typically, the "bottoms" or waste oil from refineries have been used in the manufacture of carbon black. The conventional manufacturing process requires the use of special reactors, high temperatures and the combustion of fossil fuels. The cost of this manufacturing carbon black has been on the order of twenty cents per pound.
The management of wastes produced by industry, hospitals and homes is an ever growing concern and becoming a crisis. Landfilling, the traditional waste treatment method in the United States, is now considered the method of last choice. Existing landfills are rapidly filling, are leaking and polluting the ground water and are being added to the Super Fund list. As a matter of political reality, it is becoming increasingly difficult to establish new landfills.
Incineration is becoming the waste treatment method of choice for industry. Citizen resistance to incineration, however, is strong and increasing because of the small amounts of toxic, organic chemicals, dioxins and furans, emitted by incinerators and because of the difficulties associated with the operation of incinerators. In addition, incinerators are expensive and their use has always resulted in a large increase in the cost of waste management. As a practical matter, obtaining the required governmental permits for new incinerators is becoming as difficult as obtaining the permits for new landfills.
As the environmental requirements for landfills are increased and the use of incineration increases, the costs for management of wastes is increasing rapidly. Solid waste disposal costs for 1989 increased by a factor of three, compared to 1988, in Pittsburgh and are generally between $50 and $125 per ton in New Jersey and other Northeastern States.
Infectious wastes, as for example those produced by hospitals, are currently receiving much attention because these wastes have been washing ashore on the beaches of New York and New Jersey for the past two summers. Hospitals are paying high prices, $800 or more per ton, to dispose of such wastes. Citizen opposition has stymied, as a practical matter, many hospitals in attempting to install their own incinerator. The Federal Government and many states are beginning to develop regulations over incinerators. A few States regulate infectious wastes as hazardous wastes. This regulation will further increase the costs of disposing of infectious wastes.
In the incineration process, the oxidation of the fossil fuels creates high temperatures and thus high kinetic energies. As a result of inelastic collisions among the molecules, kinetic energy is transformed into the internal energy of the molecules, usually vibrational energy, which causes chemical reactions between the organic material and oxygen to occur.
The Hobbs U.S. Pat. No. 3,648,630 Hobbs and the Hardison U.S. Pat. No. 4,667,609 describe incinerators that used infrared radiation from blackbody radiators to heat solids to promote combustion. These incinerators are similar to fossil fired incinerators in other respects. The Galloway U.S. Pat. No. 4,688,495 employs resistance heaters to heat gases to promote incineration.
The Matovich U.S. Pat. No. 3,933,434 describes the High Temperature Fluid Reactor, a chemical reactor in which the energy required is supplied by radiation. This patented reactor consists of large concentric vertical, annular radiation zones. Inert nitrogen gas flows into and through the radiation zones during operation. Reactant materials are introduced into the top of the reactor and fall vertically through the radiation in the radiation zone to promote the chemical decomposition reactions. Preprocessing of materials into extremely small, fine particles is, however, necessary to control the transit time of the reactant materials through the radiation zone. Subsequent U.S. Pat. Nos. 4,042,334; 4,044,117; 4,056,602; and 4,059,416 disclose refinements without altering the basic fluid wall.
The patented Matovich type reactor promotes decomposition of organic materials into carbon black and hydrogen by "pumping" energy into solid particles using light. The reactor creates the light flux by employing imperfect blackbody radiators, i.e. devices heated to a sufficiently high temperature that they radiate large amounts of radiation. Oxygen is excluded from the Matovich type reactor by the use of a flowing stream of inert nitrogen gas, the fluid wall, throughout the reactor. The reactant materials are at a higher energy level than the nitrogen gases because these materials are far better absorbers of radiation than the nitrogen gas.
Similarly the Westinghouse Electric Corporation has described an electric pyrolyzer system that may be used, at 3000.degree. F. and in a low oxygen or oxygen-free environment, to destroy organic solids, and sludges, and to melt inorganic solids to form a glass-like residue. This system employs a molten glass bath to entrap and remove the residue. See in this regard, the report in the May/June 1988 edition of THE HAZARDOUS WASTE CONSULTANT, especially pages 4-12 through 4-14.